1. Field of the Invention
The present relates to a display panel, and more particularly, to an LCD display panel with multi-touch function.
2. Description of the Prior Art
Due to small size and light weight, liquid crystal display (LCD) devices gradually replace traditional cathode ray tube (CRT) displays, and have been widely used in various electronic devices. With rapid shrinkage in size, there is less room for traditional input devices such as keyboards or mice. Therefore, touch panels providing tactile inputs and display function have become more and more popular.
There are various types of touch panels, such as resistive, capacitive, surface acoustic or infrared. Based on operating principles and costs, different types of LCD devices are particularly suitable for certain applications. For example, resistive type touch panels detect voltage variations caused by tactile inputs. Due to low manufacturing costs, resistive type touch panels are the most widespread technique and commonly used in consumer products such as PDAs, cellular phones, personal GPS devices, electronic dictionaries or household electronic products. Capacitive type touch panels detect capacitance variations corresponding to changes in static electricity caused by tactile inputs. With better light penetration but entailing higher manufacturing costs, capacitive type touch panels are mainly used in medium/large-size products, such as ATMs, KIOSKs or industrial equipment. By detecting acoustic waves, surface acoustic type touch panels produce clear and strong tactile signals, but are highly susceptible to the effects of external noises. Surface acoustic type touch panels are mainly used in large-size products, such as KIOSKs, automatic ticketing machines and medical equipment. Infrared type touch panels detect light interference caused by tactile inputs and can achieve 100% light penetration. However due to bulk size and low accuracy, infrared type touch panels are mainly used in high-end products, such as ATMs, office automation machinery, electronic whiteboards or industrial equipment.
Referring to FIG. 1, which is a diagram illustrating a prior art LCD device 100. The LCD device 100 includes a display area 120 and a non-display area. A plurality of parallel data lines D1-Dm, a plurality of parallel gate lines G1-Gn, a plurality of display units P11-Pmn, a plurality of parallel sensing lines SX1-SXm, a plurality of sensing units S11-Smn, and a plurality of thin film transistor (TFT) switches TFT11-TFTmn are disposed in the display area 120. Each of the sensing lines SX1-SXm is disposed between two corresponding adjacent data lines among the plurality of data lines D1-Dm. The data lines D1-Dm and the gate lines G1-GN intersect each other and form a matrix in which the display units P11-Pmn are disposed at corresponding intersections. Each display unit, comprising a TFT switch, a liquid crystal capacitor CLC and a storage capacitor CST, can control light penetration based on the charges stored in the capacitors. The sensing units S11-Smn, capable of detecting tactile inputs, are turned on (short-circuited) when receiving a touch signal. The gates of the TFT switches TFT11-TFTmn are coupled to corresponding gate lines. According to the scan signals sent by the gate lines, the sensing units S11-Smn can be electrically connected to or isolated from corresponding sensing lines SX1-SXm, respectively.
A source driver 130, a gate driver 140 and a detecting circuit 150 are disposed on the non-display area of the LCD device 100. The gate driver 140 is coupled to the gate lines G1-Gn for generating scan signals in order to turn on/off the TFT switches in corresponding display units P11-Pmn via corresponding gate lines. The source driver 130 is coupled to the data lines D1-Dm for generating data signals to corresponding display units for displaying images. The detecting circuit 150 is coupled to the sensing lines SX1-SXm for calculating touch locations according to signals received from the sensing lines SX1-SXm.